1. Field of the Invention
The present invention relates to an apparatus for achieving a spot-welded connection between small wear plates and a shoulder or fin of a turboshaft engine blade, and also to an automated process using the apparatus.
2. Description of the Prior Art
As is generally known in the construction of turboshaft aero-engines, blades of the engine may have a part, i.e. a shoulder or intermediate shoulder, also termed a fin, intended to limit the deflections which may be caused by vibrations of the blade. In order to prevent premature wear of the facing surfaces of the shoulders or fins of two adjacent blades, it is known to deposit on the faces a coating suited to the particular conditions of operation for each application, and exhibiting good frictional resistance characteristics, in particular. In addition, EP-A-0 140 736 mentions for the same purpose the use of small plates secured by welding on the edges of adjacent sectors of stator blades.
Refining the manufacture of this type of blade has led, in particular, to providing for the mounting of these added members or small plates on the active faces of the blade shoulder by using a known method of the brazing-diffusion type carried out following a thermal cycle in a vacuum treatment furnace. EP-A-0 075 497, for example, describes the technical characteristics and aspects of this operation, particularly where the added member is made of a self-brazable material not requiring the use of a supplementary material at the interface of the elements being joined.
In the manufacture of a blade comprising, in particular, the fitting of added members on the active faces of the shoulder or fin of the blade, problems are posed by the preparation steps for the fixing of these members. The invention is concerned with solving these problems, and particularly at obtaining, through the use of an automated process and appropriately adapted apparatus, good repeatability for satisfactory product quality as a result of correct and precise positioning of the members, as well as a lower manufacturing cost.